List of top Physics Questions on Moving charges and magnetism

The magnetic force acting on a charged particle carrying a charge of \( 3 \, \mu C \) in a magnetic field of 5 T acting in the \( y \)-direction, when the particle velocity is \( ( \hat{i} + \hat{j} ) \times 10^5 \, \text{ms}^{-1} \), is:
A small cube of side $1$ mm is placed at the centre of a circular loop of radius $10$ cm carrying a current of $2$ A. The magnetic energy stored inside the cube is $\alpha \times 10^{-14}$ J. The value of $\alpha$ is ————. $(\mu_0 = 4\pi \times 10^{-7} \text{ Tm/A}, \pi = 3.14)$

Consider two arrangements of wires. Find the ratio of magnetic field at the centre of the semi–circular part.

A charged particle having charge $q$ is moving perpendicularly to the uniform magnetic field with linear speed $v$ on a circular path of radius $R$. The periodic time of revolution of a particle ______.
A horizontal overhead power line carries a current of 90 A in east to west direction. What is the magnitude and direction of the magnetic field due to the current 1.2 m above the line?
In the moving coil galvanometer, if number of turns in the coil is doubled, then the current sensitivity ______ and the voltage sensitivity ______.
A current carrying solenoid is placed vertically and a particle of mass m with charge Q is released from rest. The particle moves along the axis of solenoid. If g is acceleration due to gravity then the acceleration (a) of the charged particle will satisfy:
The equilateral triangular frame has current 2A. The side of frame is \(4\sqrt{3}\) cm. Magnetic field at center C is:
Explain the principle, construction, and derive the current sensitivity of a moving coil galvanometer.
A charged particle of mass m having kinetic energy K passes undeflected through a region with electric field \(\vec{E}\) and magnetic field \(\vec{B}\) acting perpendicular to each other. The mass m of the particle will be:
An electron is moving with velocity \(v_0 \hat{i}\). If a uniform electric field \(\vec{E} = E_0 \hat{j}\) is set up in the region, the electron will:
For a circular coil of radius \(R\), magnetic field at the center is \(B_0 = 16~\mu\text{T}\). What will be the magnetic field on the axis at a distance \(x = \sqrt{3}R\) from the center?

Three very long parallel wires carrying current as shown. Find the force acting at 15 cm length of middle wire : 

An ideal solenoid is kept with its axis vertical. Current $I_0$ is flowing in the solenoid. A charge $Q$ is thrown downward inside the solenoid. The acceleration of the charged particle is then
A circular coil of radius R carries current such that magnetic field at its centre is 16\(\mu\)T. Find the magnetic field on the axis at a distance of \(\sqrt{3}R\) from the centre of coil.
A bar magnet is kept such that it is making an angle of 30$^\circ$ with the magnetic field. The torque acting on the magnet is 0.016 N-m. Find the amount of work done by external agent in rotating the magnet from most stable position to most unstable position.
A long straight current-carrying wire is placed in a uniform magnetic field of strength \( B = 0.5 \, \text{T} \). If the current in the wire is \( I = 2 \, \text{A} \) and the wire makes an angle of \( 30^\circ \) with the magnetic field, find the force per unit length on the wire.
Two identical wires, carrying equal currents are bent into circular coils A and B with 2 and 3 turns respectively. The ratio of the magnetic fields at the centres of the coils A and B is
A straight wire of length 90 cm carrying a current of 3 A is bent in the form of an equilateral triangular loop and is placed in a uniform magnetic field of $8 \times 10^{-4}$ T such that the plane of the loop makes an angle of $30^{\circ}$ with the direction of the magnetic field. The torque acting on the triangular loop is
An electron moving along a straight line with a velocity of $6.4 \times 10^7 ms^{-1}$ is subjected to a magnetic field of 3 mT. If the magnetic field is applied perpendicular to the direction of the initial path of the electron, then the radius of the circular path in which the electron moves under the influence of the magnetic field is (Mass of electron $= 9 \times 10^{-31}$ kg and charge of the electron $= 1.6 \times 10^{-19}$ C)
A proton moving with a velocity of $8\times 10^5$ ms$^{-1}$ enters a uniform magnetic field normal to the direction of the magnetic field. If the radius of the circular path of the proton in the magnetic field is $8.3$ cm, then the magnitude of the magnetic field is (Charge of proton = $1.6\times 10^{-19}$ C and mass of the proton = $1.66\times 10^{-27}$ kg)
As shown in the figure, a uniform straight wire of length $30\sqrt{3}$ cm is bent in the form of an equilateral triangle ABC. A uniform magnetic field 2T is applied parallel to the side BC. If the current through the wire is 2A, the magnitude of the force on the side AC is
A short bar magnet of magnetic moment 2.5 Am\(^2\) is kept in a uniform magnetic field of \(4 \times 10^{-5}\) T. The work done in moving the magnet from its most stable position to most unstable position is
The number of turns of two circular coils A and B are 300 and 200 respectively. The magnetic moments of the two coils A and B are in the ratio 1:2. If the two coils carry equal currents, then the ratio of radii of coils A and B is
Two long straight parallel wires carry currents of 8 A and 10 A in opposite directions. If the distance of separation between the wires is 9 cm, then the net magnetic field at a point between the two wires, which is at a perpendicular distance of 4 cm from the wire carrying 8 A current is